From 54801ed6ad4e0ea8faa67b0b4ba10debeb824d3b Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <edolstra@gmail.com>
Date: Wed, 25 Jan 2017 16:06:50 +0100
Subject: Bindings: Add a method for iterating in lexicographically sorted
 order

---
 src/libexpr/attr-set.hh | 13 +++++++++++++
 1 file changed, 13 insertions(+)

(limited to 'src/libexpr/attr-set.hh')

diff --git a/src/libexpr/attr-set.hh b/src/libexpr/attr-set.hh
index 7cf6a9c58086..e1fc2bf6d796 100644
--- a/src/libexpr/attr-set.hh
+++ b/src/libexpr/attr-set.hh
@@ -75,6 +75,19 @@ public:
 
     size_t capacity() { return capacity_; }
 
+    /* Returns the attributes in lexicographically sorted order. */
+    std::vector<const Attr *> lexicographicOrder() const
+    {
+        std::vector<const Attr *> res;
+        res.reserve(size_);
+        for (size_t n = 0; n < size_; n++)
+            res.emplace_back(&attrs[n]);
+        std::sort(res.begin(), res.end(), [](const Attr * a, const Attr * b) {
+            return (string) a->name < (string) b->name;
+        });
+        return res;
+    }
+
     friend class EvalState;
 };
 
-- 
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